Inherently stabilized deep sea floating observation stations



June 11, 1963 INHERENTLY STABILIZED DEEP SEA FLOATING OBSERVATION STATIONS R. F. DEV EREUX Filed Feb. 15, 1957 f WATE/? LINE m ORDINARY GRAVITY ugn/ a WA v55 OF R we SPACE, FUEL, E 25596 EQUIPMENT, '3 7705s srownagsrc. :1 4 EARTHOUAKES SEA WATER aALLAsrmL.

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A T TOR/VE Y 3,092,852 INHERENTLY STABILIZED DEEP SEA FLOATENG QBSERVATIGN fiTATlONS Robert F. Devereux, Del Mar, Caiif. (5636 Linda Rosa, La Jolie, Calif.) Filed Feb. 15, 1957, Ser. No. 640,356 3 Claims. (Cl. 9-8) My invention relates to floating deep sea observation towers or spar hull stations, particularly as oriented to inherent stabilization against oscillations of the surface of the sea imposed upon or against said stations; and its general purpose is through utilization of pre-determined size, length, diameter, proportions, ballasting, and water displacement of the station, to conform to a ratio coinciding with or exceeding the minimum surface wave energy normally exerted upon said station with about 25 seconds periodicity; thereby effecting an upright observation station that is practically motionless, even in storm waves, and while anchored to the bottom of the ocean.

The problem of providing a substantially steady floating platform in the deep sea for observations made therefrom, by scientists and other occupants situated thereon, has been a perplexing question, and so far as I know is at present unsolved, except as solved by my present invention. Efforts to stabilize passenger liners, using gyrostabilizers, deilectable bilge-rudders, tuned tanks, etc., attest to the fact that conventional surface hulls are deficient in this respect. Subsurface craft are somewhat more satisfactory because of their ability to remain below surface wave influence. In such case, problems of control, only partly solved by forward motion of the craft, confound investigations with not only the original motions but with motions peculiar to the submarine itself. Because access to the surface is difficult from a submarine located at a depth of one hundred feet or more below the level of the sea, its utility for the purposes of my invention is limited or precluded.

My invention primarily consists of an uprightly disposed cylindrical spar hull twenty feet or more in diameter, and six hundred feet or more in length; the wall of said hull being about one inch in thickness, and about two-thirds of the said hull being ballasted and closed off below, leaving the upper one-third of the said huil open to provide a living space for the occupants, and for storage of food, fuel and equipment, so that said hull will be upright in the water and about one-tenth of the upper part of said hull will normally extend above the level of the sea upon the immersion of said hull.

My invention further consists in attaching the inner ends of radially extending mooring lines to said hull intermediate, to the top and bottom thereof, and below the level of the sea, the outer ends of said mooring lines being fastened to floats deeply immersed in the water and secured by anchor lines to anchor blocks resting upon the bottom of the sea. I

My invention further consists in other novel features of construction, and combinations and arrangements of elements and parts illustrated in the drawing, and hereinafter more particularly described and claimed.

Reference is hereby made to the accompanying drawing, illustrating a preferred form of my invention, in which similar numerals of designation refer to similar parts throughout the several views and in which FIGURE 1 is a vertical section of a ballasted cylindrical hull embodying my invention, showing the same in upright position as normally located in the sea, with about one-tenth of said hull protruding above the water line thereof;

FIG. 2 is a greatly reduced view of the hull shown in FIG. 1, showing the attachment of said hull by radiating extending lines to floats located below the level of the sea, and the mooring of said floats to concrete anchor blocks resting upon the ocean floor, and FIG. 3 is a schematic view or graph illustrating the distribution of ocean wave energy as expressed in wave periods exerted by wind and gravity, and periods created by storms, earthquakes and tides.

Referring to the drawing, the hull 4 is of metal or other suitable material and is in the form of a gigantic elongated hollow cylindrical structure, somewhat resembling the oceanographers spar-buoy wave staff, but greatly differing therefrom in size, construction, function and water displacement, so that any tendency to vertical and lateral movement of the said hull, through action of the waves, while immersed in the ocean, is greatly minimized or rendered practically negligible; any periodic motion of the hull being made to coincide with or to exceed the minimum of surface-wave energy in the region of twentyfive seconds period.

Necessarily the said hull, to fulfill the requirements of my invention, should be at least approximately six hundred feet in length, at least approximately twenty feet in diameter, with length to diameter ratio approximately 30:1, and the wall 5 of the hull should be of substantial thickness or at least approximately one inch in thickness. As shown, the hull 4 is divided perpendicularly into three separated chambers or compartments, namely, (1) the upper chamber 6, extending vertically about one-third of the length of said hull and comprising the upper portion thereof and serving as living quarters for the observers and the crew, and also as providing storage space for drinking water, food, fuel, supplies, and equipment; (2) the long middle chamber 7 extending vertically nearly two-thirds of the length of said hull, and located below said upper chamber, said middle chamber serving as a sea water ballast tank, to which said water is admitted thereto or expelled therefrom through the seacock 8; and (3') the comparative small chamber 9 located at the extreme lower end of the hull below the middle chamber, and permanently sealed and filled with concrete or other heavy ballast.

The complete ballasting of the hull, usually is accomplished after the empty hull, ballasted only by the ballast of chamber 9, has been towed horizontally into the desired location at sea, and before being anchored as hereinafter set forth. At such time the sea-cock 8 is opened and sea water allowed to flow in and to fill or nearly to fill the chamber 7, the pressure of the air therein and the opening or closing of said cock being regulated or controlled by any suitable means well known in the art and operated from the upper chamber 6, and thereupon the hull is placed in upright position in the sea, and the chamber 6 loaded with supplies and equipment, and conditioned for occupancy as above set forth. Thereafter, the amount of sea water ballast in the chamber is carefully adjusted and regulated so that approximately only one-tenth of the longitudinal length of the hull will extend above the level of the sea. In this situation and from this construction and arrangement of parts, together with the aforesaid ballasting thereof, it follows that periodic energy, being applied to the dynamics of the hull in vertical motion at or near the bottom thereof, or at least 540 feet below the surface of the sea, results in the hydrodynamic filtering or attenuation of the energy coming from the surface Waves, thereby rendering the hull practically motionless even in storm waves when anchored in the deep ocean. From yactual experiments conducted by me, I have discovered that any wave staif hull larger than twenty feet in diameter and six hundred in length having a natural period of vertical motions of twenty-five seconds or more will always be quite stable even in the presence of most violent storm conditions at the surface of the sea; that is, the said hull may be larger than twenty feet in diameter and six hundred feet in length, and correspondingly more than approximately fifty-five hundred tons displacement, as long as the proportions of the hull allow a natural period of vertical motion of twenty-five seconds or more; but a hull smaller than a basic hull of this size, even though its natural period be twenty-five seconds, will not achieve successful results because there will not be suflicient depth at the bottom of the hull to take advantage of the natural attenuation of wave energy, produced as aforesaid by the greater construction.

Preferably, for greater utility I detachably secure, by bolts or other well known means of attachment to the top of the upper chamber 6, the penthouse 10, in the form of a flat cylindrical structure of the same material as that of the hull 4, and having a working platform 11 serving as a roof for said house, and as a landing surface for helicopters. Also, the said house may provide better living quarters for the observers and crew, and better facilities for observation and use of equipment, and as a landing stage for those going to and from the station, and for replenishment of supplies.

As shown in FIG. 2, the spar hull 4 may be anchored to the floor of the ocean and held in desired location by the mooring means there illustrated. For such purposes, I weld or otherwise firmly secure outside of and to the wall of the central portion of said hull the metallic eyelets 12, three or more in number, and equally spaced apart around said hull. To said eyelets and radially extending therefrom are secured the inner ends of the mooring lines 13, the outer ends of which are attached to anchoring lines 14 leading to the floats 15 and to the spaced anchoring blocks 16, resting upon floor of the sea. The floats 15 are preferably hermetically sealed metallic spheres, and normally are deeply immersed in the ocean water, and therefore virtually unaffected by surface wave action, and through their connection by mooring lines 14 to the hull 4 and by anchoring lines with the blocks 16, serve to keep said hull from drifting and to co-operate therewith in maintaining the same in substantially upright motionless position.

' Because of the immobility of my improved spar hull secured through the special construction and anchorage thereof as above described, my invention may not only be made available for observation and scientific pur' poses, but also it may readily be moved and set up in the ocean for aiding in the drilling of oil Wells and mining below the sea level in the ocean floor, and in the disposal of the products thereof.

Referring to FIG. 3, illustrating the distribution of wave energy as produced by wind and gravity, storms, earthquakes and the tides, the following considerations are to beborne in mind:

Generally, the ocean presents a continuous spectrum of surface wave energy ranging in periods from a fraction of a second, as in small capillary waves or ripples, to several minutes or even hours, as in the case of seismic sea waves and tides. By far the greatest concentration of surface-wave energy lies in the region of 5-15 seeonds. if one plots surface wave energy (as in the vertical ordinate in FIG. 3) against period (the horizontal) ordinate, it becomes at once evident that not only is there very little energy beyond 20 seconds period, but there is a pronounced minimum in the region of 25 secends, as indicated in FIG. 3. Here wave height, for example, probably never exceeds a few centimeters or millimeters even in great storms at'sea.

Because my invention is tuned to nesonate (to have a natural period of oscillation) of 25 seconds, in vertical motion, through carefully selected proportions, and because of the natural attenuation of surface wave energy with increase in depth, its response to the influence of waves even at its natural period of motion is very small. This may be taken as the worst possible eventuality; its response to waves of shorter period is even less, regardless of their greater energy content, because of the Q or selectivity of the hull as a resonant system and also because of the increase in natural attenuation of wave energy at depths with decrease in wave period. (Short period waves cannot send their energy very far down in the ocean.)

The hull conforms to the rise and fall of the sea surface of a period greater than 25 seconds with only the attenuation of energy with depth to minimize this motion. But because these long-period oscillations never exceed a few centimeters in amplitude this influence may 'be neglected, or allowed for by mechanical adjustment (as in the case of oil well drilling) because of the long time involved in the oscillations. Adjustment may also be made for tides (which seldom exceed the height of a foot or so in deep water in the open ocean) and the rate 'occurrence of seismic sea waves (also of the order of the height of a few inches or feet in the deep ocean) because of the long time available to bring about the adjustment, especially when automatic equipment is used to accomplish the adjusting.

The natural period of horizontal or angular motion of the hull (corresponding to pitch or roll in conventional seacraft) is much greater than its natural vertical period, placing it far beyond the reach of surface Waves of significant energy. As a result, its response in this kind of motion is very small indeed.

My invention may be embodied in other specific forms without departing from the spirit or essential character istics' thereof. The present embodiment as above set forth is, therefore, to be considered in all respects as illustrative and not restrictive, and scope of my invention being indicated by the appended claims rather than by the foregoing description, and all changes which may come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What I claim and desire to secure by Letters Patent is:

1. An inherently stabilized deep sea floating observation station, comprising a cylindrical spar hull not less than six hundred feet in length, of substantially constant diameter with length-to-diameter ratio approximately 30:1, and having a natural period of oscillation for vertical motion of about 25 seconds; said hull being thereby inherently stabilized against vertical oscillation due to surface wave action; said hull partitioned above to form a living space for human occupants; and the space below being ballasted to maintain said hull, when introduced in to the sea, in an upright position with the upper portion thereof projecting to a substantial extent above the level of'the sea.

2. A deep sea floating observation station, comprising a cylindrical spar hull not less than six hundred feet in length, with length-to-diameter ratio approximately 30:1, and having a natural period of oscillation for vertical motion of about 25 seconds, said hull being thereby inherently stabilized against vertical oscillation due to surface wave action; said hull being ballasted to maintain said hull when introduced into the sea in an upright 5 position with the upper portion thereof projecting to a and deeply submerged in the sea and substantially unafsubstantial extent above the level of the sea. fected y surface Wave action.

3. The subject matter of claim 2, and means for anchoring comprising simultaneously tautened mooring References Clted m the file of this patent lines radiating from and attached to a central portion 5 UNITED STATES PATENTS of said hull, floats deeply immersed in the sea, said floats 1,840,324 Lindquist J 12 1932 'being secured to said mooring lines, anchoring blocks 2,203,894 Cooke June 11, 1940 resting upon the bottom of the sea, and anchoring lines 2,214,453 Creed Sept. 10, 1940 secured to and between said floats and blocks, whereby 2,687,017 GerWick Aug. 24, 1954 the floats are held vertically above said anchoring blocks 10 ,77 ,669 Willis et a1. Jan. 15, 1957 

1. AN INHERENTLY STABILIZED DEEP SEA FLOATING OBSERVATION STATION, COMPRISING A CYLINDRICAL SPAR HULL NOT LESS THAN SIX HUNDRED FEET IN LENGTH, OF SUBSTANTIALLY CONSTANT DIAMETER WITH LENGTH-TO-DIAMETER RATIO APPROXIMATELY 30:1, AND HAVING A NATURAL PERIOD OF OSCILLATION FOR VERTICAL MOTION OF ABOUT 25 SECONDS; SAID HULL BEING THEREBY INHERENTLY STABILIZED AGAINST VERTICAL OSCILLATION DUE TO SURFACE WAVE ACTION; SAID HULL PARTITIONED ABOVE TO FORM A LIVING SPACE FOR HUMAN OCCUPANTS; AND THE SPACE BELOW BEING BALLASTED TO MAINTAIN SAID HULL, WHEN INTRODUCED INTO THE SEA, IN AN UPRIGHT POSITION WITH THE UPPER PORTION THEREOF PROJECTING TO A SUBSTANTIAL EXTENT ABOVE THE LEVEL OF THE SEA. 